Telephone divided multiple-switchboard system.



W. AITKEN.

TELEPHONE DIVIDED MULTIPLE SWITGHBOARD SYSTEM;

APPLIGATION FILED AUG.2-7, 1900.

927,470. Patented July 13, 1909.

2 SHEETS-BHEBT 1.'

Aumw. I mum o0. "mo-mm. wwwwm. n. c.

w. AITKEN.

TELEPHONE DIVIDED MULTIPLE SWITGHBOARD SYSTEM. APPLICATION FILED AUG.27, 1900.

927,470. Patented July 13, 1909.

2 8HEETS-SHEET 2.

UNITED STATES PATENT OFFICE.

WILLIAM AITKEN, OF MUSWELL HILL, ENGLAND.

TELEPHONE DIVIDED MULTIPLE-SWITCHBOARD SYSTEM.

citizen of Great Britain, residing at Muswell Hill, in the county of MiddleseX, England,

- h ave invented new and useful Improvements in Telephone Divided Multiple-Switehboard Systems, of which the following is a specification.

My invention relates to improvements in telephone exchange systems of the central energy type, and has for its object the provision of a so-called divided multiple system. In a system of this type the subscribers are divided into two or more groups, all of the subscribers of each group being connected to multiple jacks in a certain division of the switchboard, there being provided the same number of divisions in the central oiiice as there are groups of subscribers.

Each subscriber has an answering terminal or jack and a signal therefor in each one of the divisions at the central office, and it is the particular object of this invention to pro vide means whereby the subscriber may call any particular division at the central oflice without signaling the other divisions with which his line is connected. In the telephone directory each subscriber is designated by a number or character which indicates with which division of the central office the desired subscriber is associated, to any other subscriber wishing to communicate. Therelore, a subscriber so aetuates the substation apparatus as to display a signal in the division of the switchboard upon which the multiple oi the desired subscribers line terminates. Certain advantages are gained over systems of the straight multiple type, and these advantages assert themselves in a very pronounced. manner in large exchanges. For example, in any exchange of the twodivision type the number of multiple jacks or terminals required will be hall as great as in the one-division type, while the answering terminals in the two-division type will be twice as great as in the one-division type. However, inasmuch as in an ordinary multiple switchboard the number of multiple terminals are largely in excess of the number of answering terminals it will be seen that the number of terminals required in a two-division board is less than the number required in a single division board.

My invention has been worked out i or two and three-division switchboards and the cir- Speeification of Letters Patent.

Application filed August 27, 1900.

Patented July 13, 1909.

Serial No. 28,177.

cuits for the same are shown in the accompanying drawings, in which,

Figure 1 illustrates my invention as it would be used with a two-division switchboard Fig. 2 illustrates my invention as it would be used with. a three-division switch board, and Fig. 3 represents a modification of the two division switchboard system shownin Fig. 1, by means of which cut-oil contacts in the jacks may be used instead of cut-oil relays.

Referring to Fig. 1, the line wires A an d 13 extend. from the central oilice to the substation (1, this station being provided with the usual common battery substation apparatus, consisting in the signal d, transmitter d, receiver 3 repeating coil to w, condenser (Z and switch-hook (i In addition to these the substation. is provided with keys A and B, the depression of key A being adapted. to sever the line conductor A from the substation telephone apparatus, and connect it with earth, and the depression of the key B being adapted to sever the line conductor B from its connection with the substation apparatus and to connect it with earth. At the central office the limbs of the telephone line terminate, in one of the divisions, in multiple terminals shown. A, and in answering terminals having two contacts a" and b and in the other division, in the answering jack B having the line contacts a and 7). Each of these jacks is also provided with a third, or sleeve contact isolated from the limbs of the telephone line and adapted to serve as a test contact the multiple section. Line terminal A is connected to the armature 7t 0t cut-oil relay 7i, and thence through the normal contact 72E of this cut-oil relay, through the coil oi line relay it to the live pole of battery 2'. Line terminal 18 is connected to the spring a of cut-oil? relay 72, and thence through the normal contact 7L of such relay tl'irough the coil. of line relay R to the live pole of the battery "L. The armature R of the relay R is connected to the ground side of the battery 2' and is adapted when actuated' to make connection with the normally open contact R which is permanently connected with the line conductor A. Likcwise, the armature E 0i relay R is connected with earth. and is adapted by its actuation to make connection with the normally open contact R which is permanently connected to the line conductor B.

The cut-oil? relay 72 j has its coil connected between the sleeve contacts 01' the line jacks and the earthed pole ol battery i and is adapted by its actuation to sever the connection between the line terminals and the line relays R and B In parallel with these line relays are the line signals J and J, one being located in each of the two divisions of the switchboard, preferably just above or below the answering terminals in each division.

The cord or connecting circuit shown herewith eXtends in two talking strands between the tips (1 and q, and the rings g and of the two connecting plugs, the tip strands being carried through the windings of the repeating coil and connected to the live pole of the battery 2', and the ring strands being carried through the coils of relays 0 and 0 and the windings of a repeating coil and connected with the ground pole of the battery i. The sleeve contacts g and g are normally connected through signals p and p and 5c and :0 with the live pole of the battery 1', such signals being adapted to be shunted respectively by the resistance at and x by a corresponding actuation of relays 0 and 0.

The operation of the circuit thus described is as follows: The subscriber desiring communication with another subscriber first ascertains in which division of the switchboard the desired subscribers line is multipled. Assuming him to have found this division to be that represented by the signal J, the subscriber presses his button A, which connects the line conductor A with earth. Current now flows from the battery 01 through line relay R, normal contacts k and h of cut-ofl' relay h and over the line conductor A to earth. This current actuates relay R and connects the earth terminal of battery with the line conductor A through contacts R and R of relay R. Current in this path now locks the relay R in actuated position and maintains the actuation of the signal J whether or not the key A at the substation is actuated. The central operator before whom the signal J appears inserts her plug q into the jack indicated by the signal and thereby closes a path for current from the live pole of battery i through the resistance m, signal p and resistance :26, in parallel, to the sleeve of the plug 9, sleeve of the jack coil of the cut-off relay h to the ground pole of battery 71. Current in this path actuates the relay h, and severs the circuit of line relay R and signal J, such that the signal will now be eflaced. Energizing current now flows from the live pole of the battery i ever the tip strand of the cord circuit through the tip contact a of the answering jack over the limb A of the telephone line through the apparatus of the subscribers set, which is now in talking condition, back over the limb of the telephone line B, jack spring 6 ring conductor of the cord circuit g through coil of relay 0, and back to the ground pole of battery i. This actuates the relay 0 and maintains the signal 2) in an inoperative condition during the conversation. The operator having obtained the desired number inserts her plug g in the multiple jack of the desired line, thereby displaying her supervisory signal 19 by completing a path through the sleeve of her plug 9 and the cut-oil relay of the desired line, such signal remaining actuated until the desired subscriber answers his call, at which time the relay 0 will be energized to place a shunt about the signal p and thereby efiaee it.

Referring to Fig. 2, the line conductors A and B extend to the substation, the usual apparatus of which is here designated simply by the signaling bell d. This substation is also provided with a key A adapted by its actuation to disconnect the line conductor A from the usual telephone apparatus of the substation and connect it with earth. Likewise, the push button B is adapted by its actuation to disconnect the line conductor B from its connection with the usual telephone apparatus and connect it with earth. This station is also provided with a push button (7" adapted by its actuation to engage both push button A and push button B and thereby simultaneously disengage both of the line terminals A and B from the usual substation apparatus and connect both line terminals with earth. At the central oiiice this system is provided. with three divisions, this particular line being provided with answering and multiple terminals in one division, and with answering terminals in each of the other two divisions, these acks being respectively provided with line terminals a and Z), a and b, a and b and with sleeve or test terminals 0, c and 0 Line conductor A is connected with an armature 72 of cut-oil relay 71 and through normal contact 7L2 thereof connects with the coil of line relay 7c, and thence to the live pole of battery i, while the line conductor B is similarly connected with the armature 7r of cut-ofl' relay 71, and. thence through the coil of line relay 7c with the live pole of battery i. Relay 7c has the armature [62 adapted by its actuation to connect the ground pole of battery i with the line conductor A and also has the armature permanently connected with the coil of relay is and normally connected through contact If through signal j with the live pole of battery i. This armature 71: is adapted by its actuation to make connection with the contact k which leads through the signal to a corresponding normally open contact 74 of relay is. The armature k of relay 7c is permanently connected with the live pole of battery and normally connected through contact 16 and the signal with the coil of relay 1c and the normally closed contact k of cut-off relay 7L. Relay is also has the normally open contacts is and k adapted by pressing his button A.

by their actuation to connect the line conduct'or B with the ground pole of battery i.

In the operation of the system thus described W6 will first assume the subscriber to desirethe division of the switchboard called This closes a path from earth over the line conductor A through the normally closed contacts h and 71. of the cut-off relay 7t and the coil of line relay 7r? to the live pole of the battery i. This actuates relay 7c connecting'the ground pole of battery i through contacts 76 and k directlyon the line conductor Aythus locking tl'ie'relay 7: and completing the circuit of the signal J from ground through the contacts 7c and Wet relay 7r, contacts 76 and h of relay h, the signal J, contacts k and 7& of relay 7s, back to the'live'pole of the battery i. The actuation of relay k connectsits armature k with. the contact 76 but this does not close the circuit of signal J because its circuit is open-at contacts 7c and'lc of relay is. the insertion of the plug'the cut-otl' relay 7i: is actuated and the circuit of relay 7c and of the signalJ-is severed at the contacts h and 71. of the cut-off relay. Supposing the subscriber to d'esire the division. signaled by the actuatiorr of key B", current will flow from earth over'the conductor through the normal contacts 7L and 7r of the cut-oii relay 71. and actuate the line' relay is. The actuation of this relay closes the'contactsk' and k and connects the ground pole of battery throughthe-contactsh and'h" of relay 7!), conductor Z,

' through contacts 76 and 7c of relay 76, through the' signal J to live pole of battery. This (lisplaysthe signal J" and locks the relay 7c in actuated condition The closing of contacts 7r and'lc ofrelay 7c does not, however, display signal J because the circuit of that signal is open at contacts k and 7c of relay 7c.

Again, suppose the subscriber to desire to signal the third division he will then depress his key C, wliiclr will, by the nature of its construction, actuate both keys A and B", as before described. The simultaneous actuation of keys A and B will actuate line relays 7c and it simultaneously over thesamc circuitsas when thekeys A and B are inclividually actuated. The actuation of contactsk" and k of" relay 7t will place ground upon the line conductor A, and thereby lock relay in actuated position, and the actuationofcon'tactslr and Wei relay Zr will place ground upon the line conductor B, and thereby lock relay Zr in" its actuated condition. Signals J and J" will not now be actuated, however, the circuit of signal J being interrupted by the opening of contacts 71: and 7c of relay 7t", and the circuit of signal J being opened at contacts and 75 of relay 70. Contacts 76" and of relay 7e and contacts 7c and 5' of relay 7: now being closed the circuit of signal J 2 will be completed from the ground pole of battery through contacts 16 Upon and 7c, the signal J contacts is and It to the live pole of battery. Upon the insertion of the answering plug in the jack designated by the display of signal I the cut-oil relay 72 will be actuated and the line signal efl aced by the deenergization of the two line relays.

In Fig. 3 is shown a circuit which operates on substantially the principle of Fig. 1, this circuit being provided, however, with cut-oil contacts in the jacks instead of the cut-oil relay shown in Fig. 1. The line conductors A and B are carried serially through the contacts of the multiple and answering jacks of the terminals of one division, and through the answering jack in the terminal at the other division of the switchboard. vl hen, for example, the subscriber presses his button which grounds the line terminal A: current flows through the series contacts a", a and a and then through the coilof the line relay 7.. The actuation of the line relay places ground upon line conductor a in advance of the first series contact of the jacks, such that the line relay 7: will be locked in actuated position and the signal J will thereby be displayed until the plug is inserted in the jack, at which time the series contacts will be opened and the circuit ofthe linerelay and the signal J will be opened. The line relay then falling back to sever the ground connection with the line, the actuation of the button which places ground on the conductor B will similarly actuate linerelay and display the signal J.

My invention is here shown in connection with a specific form oi" cord circuit and specific forms of line circuits, but it is to be understood that I do not wish to beunduly limited thereto, any other desirable form of cord circuit and many variations in the shown and described line circuits being quite possible without in any way departing from the spirit or scope of my invention.

Having now particularly described and as certained the nature of my said invention and in what manner the same is to be performed, I declare that what I claim is:

1. In a telephone system, the combination with a telephoneline, of a central source of current with which the line connects, said source supplying the transmitter current for said line during conversation a plurality of signals upon the line located upon different divisions of the switchboard, switches at the substation; one for each signal and adapted to individually and selectively operate the same, and means for maintaining any of said signals in o erated conditionafter the-release of the switc ies, substantially as described.

In a telephone system, the combination with a telephone line, of a central source of current associated therewith. for both signaling and talking )urposes, a signal therefor, aswitch at the su stationto operate said sig nal from said source and a circuit for said signal closed in the operation of the same to maintain the same actuated after the release of the switch, substantially as described.

3. In a telephone system, the combination with a telephone line, of a central source of current with which the line is connected to furnish current for its transmitter during conversation, three signals for the line located upon the different divisions of the switchboard, means at the substation for indivi du ally and selectively controlling the operation of said signals, and a cut-oil relay energized when a connection is established with the line to render said signals inoperative, substantially as described.

4. In a telephone system, the combination with a telephone line, a plurality of line relays for the line, a plurality of signals for the line greater in number than said relays, means to actuate said relays from the subscribers" stations so as to selectively operate said signals, and means to render said signals inoperative when a connection is established with the line, substantially as described.

5. In a telephone system, the combination with a telephone line, of a central source of current with which the line connects to egerate its transmitter, a plurality of signals for the line also adapted to be operated by said source and located upon dii i erent divisions of a divided central switchboard, switches at the substation one for each said signal and adapted to individually and selectively operate the same, and locking circuits for said signals to maintain any of the same-operated after the release of their respective switches at the substation, substantially as described.

6. In a telephone system, the combination with a telephone line, of a central source of current with which the line is connected to furnish energy for its transmitter during eonversation, a line signal for the line on each division of a divided central switchboard, means at the substation for selectively operating any of said signals by current from said source, switches at the central oiiice for maintaining the proper signals operated after the release of said switches, and means to render said signals inoperative when connection is established with a line at any of the divisions of the switchboard, substantially as described.

7. In a telephone system, the combination with a telephone line, of line relays, one as sociated with each limb of the telephone line, means at the substation lor jointly or individually completing the circuit of said line relays, and three signals selectively displayed by the selective actuation of said relays, substantially as described.

S. In a telephone system, the combination with a telephone line, of a plurality of signals for said line located upon the dillerent divisions of a divided central. switchboard, line relays to control said signals, a central source of current having one pole normally connected with both limbs of said line for the actuation of said line relays and adapted to be connected with said line through a different path for the energization of its transmitter during conversation, a plurality of switches at the substation for the selective operation of said relays, and means at the substation for selectively operating any of said signals by the selective operation of said relays, sub stantially as described.

9. In a telephone system, the combination with a telephone line, of a plurality of signals for said line located upon the different divisions of a divided central switchboard, a central source of current for the energization of the substation transmitters, a plurality of line relays normally connected with said line for the actuation of said signals, a plurality of buttons at the substation adapted by their selective operation to individually actuate said relays, and means whereby the individual actuation of said relays will selectively control said signals, substantially as de scribed.

10. In a telephone system, the combina tion with a telephone line, of line relays having their coils normally connected, one in each limb of said telephone line, a cut-off relay vtor disconnecting the coils of said relays during conversation, a central source of current having one of its poles connected. di rectly with the coil of each of said relays, means at the substation for selectively completing the circuit of said source through said relays, an d. signals at the central orlice selectivcly controlled by the selective actuation of said relays, substantially as described.

1].. In a telephone system, the combination with a telephone line, of a plurality of: signals for said line located upon the dill erent divisions of a divided central switchboard, a central source of current normally connected. with said line for the actuation of said signals, and adapted to be connected with said line through a dill'erent path for the energization of its transmitter during conversation, and means tor individually and selectively completing the circuit of any of said signals from the substation of said line, substantially as described.

12. In a telephone system, the combination with a telephone line, of line relays having their coils normally connected, one in each limb of said telephone line, a central source of current having one of its poles connected with the coil of each of said relays, means at the substation forselectively or collectively completing the circuit of said source through said relays, and signals at the central ottice selectively controlled by the selective or collective actuation of said relays, substantially as described.

13. In a telephone system, the combination with a tele hone line, of a plurality of signals for said ine located upon the different divisions of a divided central switchboard, a central source of current normally connected with said line for the actuation of said signals and adapted to be connected with said line through a diiierent path for the energization of its transmitter during conversation, of means at the substation of said line for selectively displaying any of said signals by the temporary closing of a key, and means at the central oflice whereby said signal will be maintained actuated after said key has again been opened, and a cut-off relay adapted to be actuated when a connection is made with said line to again suppress said si nal, substantially as described.

14. .n a telephone system, the combination with a telephone line, of a cord circuit adapted to be connected therewith, a plurality of signals associated with the line and located upon the different divisions of a divided central switchboard, a central source of current for said line adapted for the actuation of said signals and to furnish current for the transmitter of said line, a line relay in each limb of the line, means whereby either of said relays may be selectively actuated from the substation of said line to selectively actuate the signals, and further means for suppressing said signal when said cord circult is connected with the line, substantially as described.

15. In a telephone system, the combination with a telephone line, of a plurality of signals greater than two located upon different divisions of a divided central switchboard, a source of current at the central 0ffice and means at the substation for causing current from said source to selectively actuate said signals, substantially as described.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

ILLIAM AITKEN.

Witnesses IIORACE WEs'r, O. B. TAHRMDIN. 

